Field of the Invention
The present invention relates to a one-component type curable composition and a one-component type waterproofing material, which enable a cured product being excellent in weather resistance and having high tensile strength and rubber hardness to be obtained and which have excellent foaming-inhibiting performance.
Description of the Related Art
Hitherto, a curable composition containing an isocyanate group-containing urethane prepolymer has been widely used in applications to, for example, an outer wall waterproofing sealing material for an architectural structure constructed by ceramic siding or the like, and an adhesive for construction members including a resin sheet, such as a vinyl chloride sheet, a tile, and a wood plate, by virtue of advantages such as the ease of working, high adhesiveness after curing, and the wide-range regulation of rubber elastic properties after curing from a low modulus to a high modulus (high stretch to low stretch). The curable composition containing an isocyanate group-containing urethane prepolymer is roughly classified into a one-component type that contains an isocyanate group-containing urethane prepolymer and is allowed to react with water in air to be cured and a two-component type in which a base compound containing an isocyanate group-containing urethane prepolymer and a curing agent containing an active hydrogen compound are mixed to be cured during construction.
The one-component type curable composition containing an isocyanate group-containing urethane prepolymer does not require a mixing operation during construction, and hence the one-component type curable composition has advantages in that the workability can be simplified and curing failure caused by a mixing mistake can be prevented. However, when the concentration of an isocyanate group is high, or the curing speed is increased, the amount of carbon dioxide to be generated is increased, or carbon dioxide is generated rapidly, for example, to thereby generate air bubbles in a cured product. Therefore, there are problems of the occurrence of troubles such as degradation in outer appearance, decrease in rubber tensile properties such as stretch, and decrease in adhesiveness. As means for solving the problems, the applicant of the present application has previously proposed technologies each involving blending an oxazolidine compound as a latent curing agent into an isocyanate group-containing urethane prepolymer (Japanese Patent Application Laid-Open Nos. 2005-206722, 2007-284547, 2007-291223, 2009-073882, and 2011-236312).
Further, the applicant of the present application has previously proposed a one-component type polyurethane waterproofing material composition using isophorone diisocyanate, which can be used for a waterproofing construction method having a feature of not applying a topcoat (Japanese Patent Application Laid-Open No. 2007-289849). However, this composition uses an alicylic isocyanate as a raw material, and hence there is a problem in that rubber hardness and mechanical strength are inferior to those in the case of using an aromatic isocyanate.
Meanwhile, the two-component type is mainly used when high weather resistance, tensile strength, and rubber hardness higher than those disclosed in Japanese Patent Application Laid-Open Nos. 2005-206722, 2007-284547, 2007-291223, 2009-073882, 2011-236312, and 2007-289849 are required.
In Japanese Patent Application Laid-Open No. 2008-222792, there is a disclosure of a two-component type urethane resin composition including: a component that contains in a particular ratio an isocyanate group-terminated urethane prepolymer, which is obtained by allowing a polyoxyalkylene polyol having a number average molecular weight of 1,000 or more and a low-molecular-weight polyol having a number average molecular weight of less than 1,000 to react with an aliphatic and/or alicyclic polyisocyanate, and a urethane polyoxazolidine compound, which is obtained by allowing an N-hydroxyalkyloxazolidine in an amount of from 0.9 mol to 1.1 mol in terms of a hydroxyl group conversion with respect to 1 mol of an isocyanate group of an aliphatic and/or alicyclic polyisocyanate to react with the polyisocyanate; and a component containing water. In Japanese Patent Application Laid-Open No. 2008-222792, the problem in that an inside of the one-component type curable composition is not cured sufficiently, the problem in that storage stability is degraded owing to water contained in a filler, and the like cannot be solved in the one-component type curable composition, and hence the two-component type curable composition is used. Further, sufficient tensile strength is not exhibited in physical properties of a cured product in Examples.